A multimillionaire Manhattan investment banker is such a cheapskate that he fought a court-ordered $1.3 million payment to a creditor — despite knowing the case would make public his affair with a business partner that led to his divorce, according to a suit.

Last July, Manhattan Supreme Court Judge Shirley Kornreich had ruled that Hugh Levey, co-founder of Gruppo, Levey & Co., owed the Virginia investment firm Pensmore the $1.3 million after he lost the money in a bad investment.

But instead of coughing up the cash, Levey engaged in a drawn-out court battle that made public documents about his 12-year affair with business partner and TV talking head Claire Gruppo, according to court papers.

The filings also unsealed Levey’s highly confidential net-worth statement that is part of his divorce. It shows that while Levey was cash-poor — he only had $500 in a checking account, $200 cash on hand and zero savings — he’s worth $29 million. The funds are tied up in a $15 million Fifth Avenue apartment, a $5 million Greenwich home and millions in various trusts and personal items.

Levey “deliberately keeps himself cash poor in order to avoid judgments, a trick he learned in a personal bankruptcy in the 1990s,” the Pensmore suit says.

Meanwhile, the 65-year-old Harvard MBA relies on his mistress, Gruppo, 61, to dole “out money to him directly and indirectly through the various trusts and entities they control together,” the suit says.

Pensmore is suing Levey to force the sale of $2 million in antiques, art and jewelry listed on his net-worth statement to pay off the debt.